An image processing apparatus equipped with an ink-jet recording unit (including a recording head) suffers from a problem that, when a recording operation such as copying or printing is not performed for a long period of time, clogging occurs in a nozzle portion of the recording head for ejecting ink, thereby causing a non-ejection state of ink. To solve this problem, there have been several attempts to provide time measuring means (such as an RTC) for generating real time data in a main body control unit of the image processing apparatus to measure a time interval in which the image processing apparatus has not performed a recording operation in accordance with this real time data so that a recovery operation of the recording head may be controlled on the basis of the time interval. For example, in accordance with the measured time interval during non-recording operation, a recording preparation operation is conducted where the number of suction recovery operations for recovering the nozzle portion of the recording head from clogging and an amount of suction are adjusted, thereby eliminating the clogging in the nozzle portion and preventing the occurrence of the non-ejection of ink.
An image processing apparatus whose main body control unit does not have time measuring means such as an RTC for the purpose of the cost reduction is not able to measure the time interval during non-recording operation and thus has difficulty in controlling the suction recovery operation in accordance with the time interval during non-recording operation. In this case, in order to prevent the clogging in the nozzle portion of the recording head in the same manner, the recording head is always subjected to suction under a maximum suction pressure (high suction) so as to eliminate the clogging in the nozzle portion at the recording preparation operation before the recording operation.
However, the image processing apparatus impartially performing the recovery operation by high suction in the recording preparation operation applies the suction recovery operation more than necessary to the recording head even when it has less possibility of causing the clogging in its nozzle portion because the time interval during non-recording operation is actually not so long, and thereby sucks excessive amount of ink in an ink tank of the recording head, consequently increasing ink consumption. Furthermore, the recording preparation operation for initial copying or printing processing at starting of the recording requires a long time period, which causes a reduction of throughput in the image processing apparatus.
The present invention was proposed to address the foregoing problem and an object thereof resides in providing an image processing apparatus and a method of controlling the same, both of which are capable of, even when a main body control unit does not have time measuring means such as an RTC for generating real time data, transmitting pseudo-time data to a recording unit before a recording operation to thereby calculate a time interval in which the recording operation has not been performed, and conducting appropriate recording preparation processing including a suction recovery operation in accordance with the calculation result.